1
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Aliaga Fandino AC, Jelínková A, Marhava P, Petrášek J, Hardtke CS. Ectopic assembly of an auxin efflux control machinery shifts developmental trajectories. THE PLANT CELL 2024; 36:1791-1805. [PMID: 38267818 PMCID: PMC11062438 DOI: 10.1093/plcell/koae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/05/2023] [Accepted: 01/18/2024] [Indexed: 01/26/2024]
Abstract
Polar auxin transport in the Arabidopsis (Arabidopsis thaliana) root tip maintains high auxin levels around the stem cell niche that gradually decrease in dividing cells but increase again once they transition toward differentiation. Protophloem differentiates earlier than other proximal tissues and employs a unique auxin "canalization" machinery that is thought to balance auxin efflux with retention. It consists of a proposed activator of PIN-FORMED (PIN) auxin efflux carriers, the cAMP-, cGMP- and Calcium-dependent (AGC) kinase PROTEIN KINASE ASSOCIATED WITH BRX (PAX); its inhibitor, BREVIS RADIX (BRX); and PHOSPHATIDYLINOSITOL-4-PHOSPHATE-5-KINASE (PIP5K) enzymes, which promote polar PAX and BRX localization. Because of a dynamic PAX-BRX-PIP5K interplay, the net cellular output of this machinery remains unclear. In this study, we deciphered the dosage-sensitive regulatory interactions among PAX, BRX, and PIP5K by their ectopic expression in developing xylem vessels. The data suggest that the dominant collective output of the PAX-BRX-PIP5K module is a localized reduction in PIN abundance. This requires PAX-stimulated clathrin-mediated PIN endocytosis upon site-specific phosphorylation, which distinguishes PAX from other AGC kinases. An ectopic assembly of the PAX-BRX-PIP5K module is sufficient to cause cellular auxin retention and affects root growth vigor by accelerating the trajectory of xylem vessel development. Our data thus provide direct evidence that local manipulation of auxin efflux alters the timing of cellular differentiation in the root.
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Affiliation(s)
| | - Adriana Jelínková
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 165 02, Czech Republic
| | - Petra Marhava
- Department of Plant Molecular Biology, University of Lausanne, Lausanne CH-1015, Switzerland
| | - Jan Petrášek
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 165 02, Czech Republic
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Lausanne CH-1015, Switzerland
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2
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Hardtke CS. Phloem development. THE NEW PHYTOLOGIST 2023. [PMID: 37243530 DOI: 10.1111/nph.19003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 04/13/2023] [Indexed: 05/29/2023]
Abstract
The evolution of the plant vascular system is a key process in Earth history because it enabled plants to conquer land and transform the terrestrial surface. Among the vascular tissues, the phloem is particularly intriguing because of its complex functionality. In angiosperms, its principal components are the sieve elements, which transport phloem sap, and their neighboring companion cells. Together, they form a functional unit that sustains sap loading, transport, and unloading. The developmental trajectory of sieve elements is unique among plant cell types because it entails selective organelle degradation including enucleation. Meticulous analyses of primary, so-called protophloem in the Arabidopsis thaliana root meristem have revealed key steps in protophloem sieve element formation at single-cell resolution. A transcription factor cascade connects specification with differentiation and also orchestrates phloem pole patterning via noncell-autonomous action of sieve element-derived effectors. Reminiscent of vascular tissue patterning in secondary growth, these involve receptor kinase pathways, whose antagonists guide the progression of sieve element differentiation. Receptor kinase pathways may also safeguard phloem formation by maintaining the developmental plasticity of neighboring cell files. Our current understanding of protophloem development in the A. thaliana root has reached sufficient detail to instruct molecular-level investigation of phloem formation in other organs.
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Affiliation(s)
- Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, CH-1015, Lausanne, Switzerland
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3
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Chen L, Cochran AM, Waite JM, Shirasu K, Bemis SM, Torii KU. Direct attenuation of Arabidopsis ERECTA signalling by a pair of U-box E3 ligases. NATURE PLANTS 2023; 9:112-127. [PMID: 36539597 PMCID: PMC9873567 DOI: 10.1038/s41477-022-01303-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Plants sense a myriad of signals through cell-surface receptors to coordinate their development and environmental response. The Arabidopsis ERECTA receptor kinase regulates diverse developmental processes via perceiving multiple EPIDERMAL PATTERNING FACTOR (EPF)/EPF-LIKE peptide ligands. How the activated ERECTA protein is turned over is unknown. Here we identify two closely related plant U-box ubiquitin E3 ligases, PUB30 and PUB31, as key attenuators of ERECTA signalling for two developmental processes: inflorescence/pedicel growth and stomatal development. Loss-of-function pub30 pub31 mutant plants exhibit extreme inflorescence/pedicel elongation and reduced stomatal numbers owing to excessive ERECTA protein accumulation. Ligand activation of ERECTA leads to phosphorylation of PUB30/31 via BRI1-ASSOCIATED KINASE1 (BAK1), which acts as a coreceptor kinase and a scaffold to promote PUB30/31 to associate with and ubiquitinate ERECTA for eventual degradation. Our work highlights PUB30 and PUB31 as integral components of the ERECTA regulatory circuit that ensure optimal signalling outputs, thereby defining the role for PUB proteins in developmental signalling.
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Affiliation(s)
- Liangliang Chen
- Howard Hughes Medical Institute and Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Department of Biology, University of Washington, Seattle, WA, USA
| | - Alicia M Cochran
- Howard Hughes Medical Institute and Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Jessica M Waite
- Department of Biology, University of Washington, Seattle, WA, USA
- USDA-ARS Tree Fruit Research Laboratory, Wenatchee, WA, USA
| | - Ken Shirasu
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Shannon M Bemis
- Department of Biology, University of Washington, Seattle, WA, USA
| | - Keiko U Torii
- Howard Hughes Medical Institute and Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.
- Department of Biology, University of Washington, Seattle, WA, USA.
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4
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Aliaga Fandino AC, Hardtke CS. Auxin transport in developing protophloem: A case study in canalization. JOURNAL OF PLANT PHYSIOLOGY 2022; 269:153594. [PMID: 34953411 DOI: 10.1016/j.jplph.2021.153594] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/03/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Spatiotemporal cues orchestrate the development of organs and cellular differentiation in multicellular organisms. For instance, in the root apical meristem an auxin gradient patterns the transition from stem cell maintenance to transit amplification and eventual differentiation. Among the proximal tissues generated by this growth apex, the early, so-called protophloem, is the first tissue to differentiate. This observation has been linked to increased auxin activity in the developing protophloem sieve element cell files as compared to the neighboring tissues. Here we review recent progress in the characterization of the unique mechanism by which auxin canalizes its activity in the developing protophloem and fine-tunes its own transport to guide proper timing of protophloem sieve element differentiation.
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Affiliation(s)
- Ana Cecilia Aliaga Fandino
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland.
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5
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Koh SWH, Marhava P, Rana S, Graf A, Moret B, Bassukas AEL, Zourelidou M, Kolb M, Hammes UZ, Schwechheimer C, Hardtke CS. Mapping and engineering of auxin-induced plasma membrane dissociation in BRX family proteins. THE PLANT CELL 2021; 33:1945-1960. [PMID: 33751121 PMCID: PMC8290284 DOI: 10.1093/plcell/koab076] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 03/03/2021] [Indexed: 05/04/2023]
Abstract
Angiosperms have evolved the phloem for the long-distance transport of metabolites. The complex process of phloem development involves genes that only occur in vascular plant lineages. For example, in Arabidopsis thaliana, the BREVIS RADIX (BRX) gene is required for continuous root protophloem differentiation, together with PROTEIN KINASE ASSOCIATED WITH BRX (PAX). BRX and its BRX-LIKE (BRXL) homologs are composed of four highly conserved domains including the signature tandem BRX domains that are separated by variable spacers. Nevertheless, BRX family proteins have functionally diverged. For instance, BRXL2 can only partially replace BRX in the root protophloem. This divergence is reflected in physiologically relevant differences in protein behavior, such as auxin-induced plasma membrane dissociation of BRX, which is not observed for BRXL2. Here we dissected the differential functions of BRX family proteins using a set of amino acid substitutions and domain swaps. Our data suggest that the plasma membrane-associated tandem BRX domains are both necessary and sufficient to convey the biological outputs of BRX function and therefore constitute an important regulatory entity. Moreover, PAX target phosphosites in the linker between the two BRX domains mediate the auxin-induced plasma membrane dissociation. Engineering these sites into BRXL2 renders this modified protein auxin-responsive and thereby increases its biological activity in the root protophloem context.
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Affiliation(s)
- Samuel W H Koh
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Petra Marhava
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Surbhi Rana
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Alina Graf
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Bernard Moret
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | | | - Melina Zourelidou
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Martina Kolb
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Ulrich Z Hammes
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Claus Schwechheimer
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
- Author for correspondence:
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6
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Qi X, Yoshinari A, Bai P, Maes M, Zeng SM, Torii KU. The manifold actions of signaling peptides on subcellular dynamics of a receptor specify stomatal cell fate. eLife 2020; 9:58097. [PMID: 32795387 PMCID: PMC7470842 DOI: 10.7554/elife.58097] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 08/14/2020] [Indexed: 12/19/2022] Open
Abstract
Receptor endocytosis is important for signal activation, transduction, and deactivation. However, how a receptor interprets conflicting signals to adjust cellular output is not clearly understood. Using genetic, cell biological, and pharmacological approaches, we report here that ERECTA-LIKE1 (ERL1), the major receptor restricting plant stomatal differentiation, undergoes dynamic subcellular behaviors in response to different EPIDERMAL PATTERNING FACTOR (EPF) peptides. Activation of ERL1 by EPF1 induces rapid ERL1 internalization via multivesicular bodies/late endosomes to vacuolar degradation, whereas ERL1 constitutively internalizes in the absence of EPF1. The co-receptor, TOO MANY MOUTHS is essential for ERL1 internalization induced by EPF1 but not by EPFL6. The peptide antagonist, Stomagen, triggers retention of ERL1 in the endoplasmic reticulum, likely coupled with reduced endocytosis. In contrast, the dominant-negative ERL1 remained dysfunctional in ligand-induced subcellular trafficking. Our study elucidates that multiple related yet unique peptides specify cell fate by deploying the differential subcellular dynamics of a single receptor.
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Affiliation(s)
- Xingyun Qi
- Howard Hughes Medical Institute and Department of Biology, University of Washington, Seattle, United States
| | - Akira Yoshinari
- Institute of Transformative Biomolecules (WPI-ITbM), Nagoya University, Aichi, Japan
| | - Pengfei Bai
- Howard Hughes Medical Institute and Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
| | - Michal Maes
- Howard Hughes Medical Institute and Department of Biology, University of Washington, Seattle, United States
| | - Scott M Zeng
- Howard Hughes Medical Institute and Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States.,Department of Physics, University of Washington, Seattle, United States
| | - Keiko U Torii
- Howard Hughes Medical Institute and Department of Biology, University of Washington, Seattle, United States.,Institute of Transformative Biomolecules (WPI-ITbM), Nagoya University, Aichi, Japan.,Howard Hughes Medical Institute and Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
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7
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Moret B, Marhava P, Aliaga Fandino AC, Hardtke CS, Ten Tusscher KHW. Local auxin competition explains fragmented differentiation patterns. Nat Commun 2020; 11:2965. [PMID: 32528082 PMCID: PMC7289883 DOI: 10.1038/s41467-020-16803-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/20/2020] [Indexed: 01/04/2023] Open
Abstract
Trajectories of cellular ontogeny are tightly controlled and often involve feedback-regulated molecular antagonism. For example, sieve element differentiation along developing protophloem cell files of Arabidopsis roots requires two antagonistic regulators of auxin efflux. Paradoxically, loss-of-function in either regulator triggers similar, seemingly stochastic differentiation failures of individual sieve element precursors. Here we show that these patterning defects are distinct and non-random. They can be explained by auxin-dependent bistability that emerges from competition for auxin between neighboring cells. This bistability depends on the presence of an auxin influx facilitator, and can be triggered by either flux enhancement or repression. Our results uncover a hitherto overlooked aspect of auxin uptake, and highlight the contributions of local auxin influx, efflux and biosynthesis to protophloem formation. Moreover, the combined experimental-modeling approach suggests that without auxin efflux homeostasis, auxin influx interferes with coordinated differentiation. Sieve element differentiation in Arabidopsis roots requires two antagonistic regulators of auxin efflux, BRX and PAX. Here the authors show that together they coordinate sieve element formation by preventing cell fate bistability emerging from AUX1-mediated competition for auxin between neighboring cells.
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Affiliation(s)
- Bernard Moret
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
| | - Petra Marhava
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
| | - Ana Cecilia Aliaga Fandino
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland.
| | - Kirsten H W Ten Tusscher
- Theoretical Biology, Department of Biology, Utrecht University, 3584 CH, Utrecht, The Netherlands.
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8
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Abstract
The root meristem-one of the plant's centers of continuous growth-is a conveyer belt in which cells of different identities are pushed through gradients along the root's longitudinal axis. An auxin gradient has long been implicated in controlling the progression of cell states in the root meristem. Recent work has shown that a PLETHORA (PLT) protein transcription factor gradient, which is under a delayed auxin response, has a dose-dependent effect on the differentiation state of cells. The direct effect of auxin concentration on differential transcriptional outputs remains unclear. Genomic and other analyses of regulatory sequences show that auxin responses are likely controlled by combinatorial inputs from transcription factors outside the core auxin signaling pathway. The passage through the meristem exposes cells to varying positional signals that could help them interpret auxin inputs independent of gradient effects. One open question is whether cells process information from the changes in the gradient over time as they move through the auxin gradient.
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Affiliation(s)
- Bruno Guillotin
- New York University, The Department of Biology, The Center for Genomics and Systems Biology, New York, NY, United States
| | - Kenneth D Birnbaum
- New York University, The Department of Biology, The Center for Genomics and Systems Biology, New York, NY, United States.
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9
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Marhava P, Aliaga Fandino AC, Koh SW, Jelínková A, Kolb M, Janacek DP, Breda AS, Cattaneo P, Hammes UZ, Petrášek J, Hardtke CS. Plasma Membrane Domain Patterning and Self-Reinforcing Polarity in Arabidopsis. Dev Cell 2020; 52:223-235.e5. [DOI: 10.1016/j.devcel.2019.11.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/08/2019] [Accepted: 11/21/2019] [Indexed: 10/25/2022]
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10
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Aliaga Fandino AC, Kim H, Rademaker JD, Lee JY. Reprogramming of the cambium regulators during adventitious root development upon wounding of storage tap roots in radish ( Raphanus sativus L.). Biol Open 2019; 8:bio.039677. [PMID: 30787007 PMCID: PMC6451342 DOI: 10.1242/bio.039677] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cambium contains a stem cell population that produces xylem and phloem tissues in a radial direction during the secondary growth stage. The growth of many storage roots, including in the radish, Raphanus sativus L., also depends on cambium. Interestingly, we observed numerous adventitious roots (ARs) emerging from the cambia of cut surfaces when the bases of radish storage tap roots were removed. Previous studies in Arabidopsis showed that the WOX11/12 pathway regulates AR initiation and meristem establishment in an auxin-dependent manner. Here, we provide evidence indicating the evolutionary conservation of the WOX11/12 pathway during the AR development in radishes. Additionally, we found that expression of two cambium regulators, PXY and WOX4, is induced in the cambium regions that are connected to emerging ARs via vascularization. Both AR formation and genes associated with this were induced by exogenous auxin. Our research suggests that some key cambium regulators might be reprogrammed to aid in the AR development in concert with the WOX11/12 pathway.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Ana Cecilia Aliaga Fandino
- School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Hyoujin Kim
- School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jesse David Rademaker
- School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.,Department of Behavioural Biology, University Utrecht, Padualaan 8, Utrecht 3584CH, The Netherlands
| | - Ji-Young Lee
- School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea .,Plant Genomics and Breeding Institute, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
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11
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Marhava P, Bassukas AEL, Zourelidou M, Kolb M, Moret B, Fastner A, Schulze WX, Cattaneo P, Hammes UZ, Schwechheimer C, Hardtke CS. A molecular rheostat adjusts auxin flux to promote root protophloem differentiation. Nature 2018; 558:297-300. [DOI: 10.1038/s41586-018-0186-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 04/24/2018] [Indexed: 01/30/2023]
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12
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Blob B, Heo JO, Helariutta Y. Phloem differentiation: an integrative model for cell specification. JOURNAL OF PLANT RESEARCH 2018; 131:31-36. [PMID: 29204753 PMCID: PMC5762813 DOI: 10.1007/s10265-017-0999-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/18/2017] [Indexed: 05/21/2023]
Abstract
Plant vasculature consists of two major conductive cell types, xylem tracheary elements and phloem sieve elements (SEs). Both cell types undergo a highly specialized differentiation process. The root meristem of Arabidopsis displays a stereotypical anatomy in which the central vasculature is surrounded by concentric layers of outer tissues. Each cell file is derived from stem cells located in the root tip. A series of formative and proliferative divisions take place in the meristem; these are followed by cell expansion and differentiation. Protophloem differentiation is unique in being complete only 20-25 cells away from the first stem cell, and during the differentiation process the cells lose several organelles, including the nucleus, while the remaining organelles are rearranged. Defects in SE development have been shown to result in impaired auxin transport and response and therefore systemically affect root growth. Although a few genes have been demonstrated to function in phloem development, detailed analyses and a comprehensive understanding of sieve element development (i.e. how often the stem cells divide, how frequently enucleation takes place, and how SE development is coordinated between cell division and differentiation on a molecular level) are still lacking. Advanced live-imaging techniques which enable prolonged time-lapse captures of root tip growth as well as single-cell transcriptomic analysis of the 20-25 cells in the SE file could help resolve these questions. In addition, understanding the interplay between the PLETHORA (PLT) gradient, which is known to govern the root zonation, and phloem development within the root meristem could shed light on the rapidity of SE differentiation and its importance to the meristem.
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Affiliation(s)
- Bernhard Blob
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge, CB2 1LR, UK
| | - Jung-Ok Heo
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge, CB2 1LR, UK
- Institute of Biotechnology, University of Helsinki, 00014, Helsinki, Finland
| | - Yka Helariutta
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge, CB2 1LR, UK.
- Institute of Biotechnology, University of Helsinki, 00014, Helsinki, Finland.
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13
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Kang YH, Breda A, Hardtke CS. Brassinosteroid signaling directs formative cell divisions and protophloem differentiation in Arabidopsis root meristems. Development 2017; 144:272-280. [PMID: 28096215 PMCID: PMC5394764 DOI: 10.1242/dev.145623] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/28/2016] [Indexed: 01/22/2023]
Abstract
Brassinosteroids (BRs) trigger an intracellular signaling cascade through its receptors BR INSENSITIVE 1 (BRI1), BRI1-LIKE 1 (BRL1) and BRL3. Recent studies suggest that BR-independent inputs related to vascular differentiation, for instance root protophloem development, modulate downstream BR signaling components. Here, we report that protophloem sieve element differentiation is indeed impaired in bri1 brl1 brl3 mutants, although this effect might not be mediated by canonical downstream BR signaling components. We also found that their small meristem size is entirely explained by reduced cell elongation, which is, however, accompanied by supernumerary formative cell divisions in the radial dimension. Thus, reduced cell expansion in conjunction with growth retardation, because of the need to accommodate supernumerary formative divisions, can account for the overall short root phenotype of BR signaling mutants. Tissue-specific re-addition of BRI1 activity partially rescued subsets of these defects through partly cell-autonomous, partly non-cell-autonomous effects. However, protophloem-specific BRI1 expression essentially rescued all major bri1 brl1 brl3 root meristem phenotypes. Our data suggest that BR perception in the protophloem is sufficient to systemically convey BR action in the root meristem context. Highlighted article: In addition to controlling cell expansion, brassinosteroid signaling acts cell-autonomously and non-cell-autonomously to promote protophloem differentiation and restrict formative divisions in root meristems.
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Affiliation(s)
- Yeon Hee Kang
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Alice Breda
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
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14
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Cattaneo P, Hardtke CS. BIG BROTHER Uncouples Cell Proliferation from Elongation in the Arabidopsis Primary Root. PLANT & CELL PHYSIOLOGY 2017; 58:1519-1527. [PMID: 28922745 PMCID: PMC5914324 DOI: 10.1093/pcp/pcx091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 06/25/2017] [Indexed: 05/10/2023]
Abstract
Plant organ size is sensitive to environmental conditions, but is also limited by hardwired genetic constraints. In Arabidopsis, a few organ size regulators have been identified. Among them, the BIG BROTHER (BB) gene has a prominent role in the determination of flower organ and leaf size. BB loss-of-function mutations result in a prolonged proliferation phase during leaf(-like) organ formation, and consequently larger leaves, petals and sepals. Whether BB has a similar role in root growth is unknown. Here we describe a novel bb allele which carries a P235L point mutation in the BB RING finger domain. This allele behaves similarly to described bb loss-of-function alleles and displays increased root meristem size due to a higher number of dividing, meristematic cells. In contrast, mature cell length is unaffected. The increased meristematic activity does not, however, translate into overall enhanced root elongation, possibly because bb mutation also results in an increased number of cell files in the vascular cylinder. These extra formative divisions might offset any growth acceleration by extra meristematic divisions. Thus, although BB dampens root cell proliferation, the consequences on macroscopic root growth are minor. However, bb mutation accelerates overall root growth when introduced into sensitized backgrounds. For example, it partially rescues the short root phenotypes of the brevis radix and octopus mutants, but does not complement their phloem differentiation or transport defects. In summary, we provide evidence that BB acts conceptually similarly in leaf(-like) organs and the primary root, and uncouples cell proliferation from elongation in the root meristem.
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Affiliation(s)
- Pietro Cattaneo
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Christian S. Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
- Corresponding author: E-mail, ; Fax, +41-21-692-4150
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15
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Auxin minimum triggers the developmental switch from cell division to cell differentiation in the Arabidopsis root. Proc Natl Acad Sci U S A 2017; 114:E7641-E7649. [PMID: 28831001 DOI: 10.1073/pnas.1705833114] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In multicellular organisms, a stringent control of the transition between cell division and differentiation is crucial for correct tissue and organ development. In the Arabidopsis root, the boundary between dividing and differentiating cells is positioned by the antagonistic interaction of the hormones auxin and cytokinin. Cytokinin affects polar auxin transport, but how this impacts the positional information required to establish this tissue boundary, is still unknown. By combining computational modeling with molecular genetics, we show that boundary formation is dependent on cytokinin's control on auxin polar transport and degradation. The regulation of both processes shapes the auxin profile in a well-defined auxin minimum. This auxin minimum positions the boundary between dividing and differentiating cells, acting as a trigger for this developmental transition, thus controlling meristem size.
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16
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Fozard JA, Bennett MJ, King JR, Jensen OE. Hybrid vertex-midline modelling of elongated plant organs. Interface Focus 2016; 6:20160043. [PMID: 27708766 PMCID: PMC4992745 DOI: 10.1098/rsfs.2016.0043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We describe a method for the simulation of the growth of elongated plant organs, such as seedling roots. By combining a midline representation of the organ on a tissue scale and a vertex-based representation on the cell scale, we obtain a multiscale method, which is able to both simulate organ growth and incorporate cell-scale processes. Equations for the evolution of the midline are obtained, which depend on the cell-wall properties of individual cells through appropriate averages over the vertex-based representation. The evolution of the organ midline is used to deform the cellular-scale representation. This permits the investigation of the regulation of organ growth through the cell-scale transport of the plant hormone auxin. The utility of this method is demonstrated in simulating the early stages of the response of a root to gravity, using a vertex-based template acquired from confocal imaging. Asymmetries in the concentrations of auxin between the upper and lower sides of the root lead to bending of the root midline, reflecting a gravitropic response.
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Affiliation(s)
- John A. Fozard
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - Malcolm J. Bennett
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - John R. King
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Oliver E. Jensen
- School of Mathematics, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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17
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Cheng F, Sun R, Hou X, Zheng H, Zhang F, Zhang Y, Liu B, Liang J, Zhuang M, Liu Y, Liu D, Wang X, Li P, Liu Y, Lin K, Bucher J, Zhang N, Wang Y, Wang H, Deng J, Liao Y, Wei K, Zhang X, Fu L, Hu Y, Liu J, Cai C, Zhang S, Zhang S, Li F, Zhang H, Zhang J, Guo N, Liu Z, Liu J, Sun C, Ma Y, Zhang H, Cui Y, Freeling MR, Borm T, Bonnema G, Wu J, Wang X. Subgenome parallel selection is associated with morphotype diversification and convergent crop domestication in Brassica rapa and Brassica oleracea. Nat Genet 2016; 48:1218-24. [PMID: 27526322 DOI: 10.1038/ng.3634] [Citation(s) in RCA: 205] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 07/01/2016] [Indexed: 12/21/2022]
Abstract
Brassica species, including crops such as cabbage, turnip and oilseed, display enormous phenotypic variation. Brassica genomes have all undergone a whole-genome triplication (WGT) event with unknown effects on phenotype diversification. We resequenced 199 Brassica rapa and 119 Brassica oleracea accessions representing various morphotypes and identified signals of selection at the mesohexaploid subgenome level. For cabbage morphotypes with their typical leaf-heading trait, we identified four subgenome loci that show signs of parallel selection among subgenomes within B. rapa, as well as four such loci within B. oleracea. Fifteen subgenome loci are under selection and are shared by these two species. We also detected strong subgenome parallel selection linked to the domestication of the tuberous morphotypes, turnip (B. rapa) and kohlrabi (B. oleracea). Overall, we demonstrated that the mesohexaploidization of the two Brassica genomes contributed to their diversification into heading and tuber-forming morphotypes through convergent subgenome parallel selection of paralogous genes.
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Affiliation(s)
- Feng Cheng
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Rifei Sun
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Xilin Hou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Weigang, Nanjing, China
| | | | - Fenglan Zhang
- Beijing Academy of Agriculture and Forestry Science (BAAFS), Beijing Vegetable Research Center (BVRC), Beijing, China
| | - Yangyong Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Bo Liu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Jianli Liang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Mu Zhuang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Yunxia Liu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Dongyuan Liu
- Biomarker Technologies Corporation, Beijing, China
| | - Xiaobo Wang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Pingxia Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Yumei Liu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Ke Lin
- Wageningen UR Plant Breeding, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Johan Bucher
- Wageningen UR Plant Breeding, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Ningwen Zhang
- Wageningen UR Plant Breeding, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Yan Wang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Hui Wang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Jie Deng
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Yongcui Liao
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Keyun Wei
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Xueming Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Lixia Fu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Yunyan Hu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Jisheng Liu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Chengcheng Cai
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Shujiang Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Shifan Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Fei Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Hui Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Jifang Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Ning Guo
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Zhiyuan Liu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Jin Liu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Chao Sun
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Yuan Ma
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Haijiao Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Yang Cui
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Micheal R Freeling
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkley, California, USA
| | - Theo Borm
- Wageningen UR Plant Breeding, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Guusje Bonnema
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China.,Wageningen UR Plant Breeding, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Jian Wu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
| | - Xiaowu Wang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China
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18
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Kang YH, Hardtke CS. Arabidopsis MAKR5 is a positive effector of BAM3-dependent CLE45 signaling. EMBO Rep 2016; 17:1145-54. [PMID: 27354416 DOI: 10.15252/embr.201642450] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/02/2016] [Indexed: 11/09/2022] Open
Abstract
Receptor kinases convey diverse environmental and developmental inputs by sensing extracellular ligands. In plants, one group of receptor-like kinases (RLKs) is characterized by extracellular leucine-rich repeat (LRR) domains, which interact with various ligands that include the plant hormone brassinosteroid and peptides of the CLAVATA3/EMBRYO SURROUNDING REGION (CLE) type. For instance, the CLE45 peptide requires the LRR-RLK BARELY ANY MERISTEM 3 (BAM3) to prevent protophloem formation in Arabidopsis root meristems. Here, we show that other proposed CLE45 receptors, the two redundantly acting LRR-RLKs STERILITY-REGULATING KINASE MEMBER 1 (SKM1) and SKM2 (which perceive CLE45 in the context of pollen tube elongation), cannot substitute for BAM3 in the root. Moreover, we identify MEMBRANE-ASSOCIATED KINASE REGULATOR 5 (MAKR5) as a post-transcriptionally regulated amplifier of the CLE45 signal that acts downstream of BAM3. MAKR5 belongs to a small protein family whose prototypical member, BRI1 KINASE INHIBITOR 1, is an essentially negative regulator of brassinosteroid signaling. By contrast, MAKR5 is a positive effector of CLE45 signaling, revealing an unexpected diversity in the conceptual roles of MAKR genes in different signaling pathways.
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Affiliation(s)
- Yeon Hee Kang
- Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland
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19
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Barbier de Reuille P, Routier-Kierzkowska AL, Kierzkowski D, Bassel GW, Schüpbach T, Tauriello G, Bajpai N, Strauss S, Weber A, Kiss A, Burian A, Hofhuis H, Sapala A, Lipowczan M, Heimlicher MB, Robinson S, Bayer EM, Basler K, Koumoutsakos P, Roeder AHK, Aegerter-Wilmsen T, Nakayama N, Tsiantis M, Hay A, Kwiatkowska D, Xenarios I, Kuhlemeier C, Smith RS. MorphoGraphX: A platform for quantifying morphogenesis in 4D. eLife 2015; 4:05864. [PMID: 25946108 PMCID: PMC4421794 DOI: 10.7554/elife.05864] [Citation(s) in RCA: 301] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 04/03/2015] [Indexed: 12/25/2022] Open
Abstract
Morphogenesis emerges from complex multiscale interactions between genetic and mechanical processes. To understand these processes, the evolution of cell shape, proliferation and gene expression must be quantified. This quantification is usually performed either in full 3D, which is computationally expensive and technically challenging, or on 2D planar projections, which introduces geometrical artifacts on highly curved organs. Here we present MorphoGraphX ( www.MorphoGraphX.org), a software that bridges this gap by working directly with curved surface images extracted from 3D data. In addition to traditional 3D image analysis, we have developed algorithms to operate on curved surfaces, such as cell segmentation, lineage tracking and fluorescence signal quantification. The software's modular design makes it easy to include existing libraries, or to implement new algorithms. Cell geometries extracted with MorphoGraphX can be exported and used as templates for simulation models, providing a powerful platform to investigate the interactions between shape, genes and growth.
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Affiliation(s)
| | - Anne-Lise Routier-Kierzkowska
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Daniel Kierzkowski
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - George W Bassel
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | | | | | - Namrata Bajpai
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Sören Strauss
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Alain Weber
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Annamaria Kiss
- Reproduction et Développement des Plantes, Ecole Normale Supérieure de Lyon, Lyon, France
- Laboratoire Joliot Curie, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Agata Burian
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
- Department of Biophysics and Morphogenesis of Plants, University of Silesia, Katowice, Poland
| | - Hugo Hofhuis
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Aleksandra Sapala
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Marcin Lipowczan
- Department of Biophysics and Morphogenesis of Plants, University of Silesia, Katowice, Poland
| | | | - Sarah Robinson
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Emmanuelle M Bayer
- Laboratory of Membrane Biogenesis, University of Bordeaux, Bordeaux, France
| | - Konrad Basler
- Institute of Molecular Life Sciences, Zurich, Switzerland
| | | | - Adrienne HK Roeder
- Weill Institute for Cell and Molecular Biology and School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, United States
| | | | - Naomi Nakayama
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Miltos Tsiantis
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Angela Hay
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Dorota Kwiatkowska
- Department of Biophysics and Morphogenesis of Plants, University of Silesia, Katowice, Poland
| | | | - Cris Kuhlemeier
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Richard S Smith
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne, Germany
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20
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Karve R, Iyer-Pascuzzi AS. Digging deeper: high-resolution genome-scale data yields new insights into root biology. CURRENT OPINION IN PLANT BIOLOGY 2015; 24:24-30. [PMID: 25636037 DOI: 10.1016/j.pbi.2015.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 05/14/2023]
Abstract
Development in multicellular organisms is the result of designated cellular programs occurring at specific points in time and space. The root is an excellent model to address how spatio-temporal complexity impacts organ development. High-resolution 'omic' approaches have delineated the transcriptional, proteomic, metabolomic, and small RNA profiles of multiple cell types in the Arabidopsis root. Similar approaches have shed light on root cell-type specific transcriptional programs in rice and soybean. These data are being used to identify specific spatio-temporal mechanisms of root development, dissect regulatory networks that control cell identity, and understand hormone responses in the root. Computational modeling of these data combined with new advances in imaging technologies is generating new biological insights into root growth and development.
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Affiliation(s)
- Rucha Karve
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, United States
| | - Anjali S Iyer-Pascuzzi
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, United States.
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21
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Long Y, Smet W, Cruz-Ramírez A, Castelijns B, de Jonge W, Mähönen AP, Bouchet BP, Perez GS, Akhmanova A, Scheres B, Blilou I. Arabidopsis BIRD Zinc Finger Proteins Jointly Stabilize Tissue Boundaries by Confining the Cell Fate Regulator SHORT-ROOT and Contributing to Fate Specification. THE PLANT CELL 2015; 27:1185-99. [PMID: 25829440 PMCID: PMC4558684 DOI: 10.1105/tpc.114.132407] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 02/10/2015] [Accepted: 03/10/2015] [Indexed: 05/18/2023]
Abstract
Plant cells cannot rearrange their positions; therefore, sharp tissue boundaries must be accurately programmed. Movement of the cell fate regulator SHORT-ROOT from the stele to the ground tissue has been associated with transferring positional information across tissue boundaries. The zinc finger BIRD protein JACKDAW has been shown to constrain SHORT-ROOT movement to a single layer, and other BIRD family proteins were postulated to counteract JACKDAW's role in restricting SHORT-ROOT action range. Here, we report that regulation of SHORT-ROOT movement requires additional BIRD proteins whose action is critical for the establishment and maintenance of the boundary between stele and ground tissue. We show that BIRD proteins act in concert and not in opposition. The exploitation of asymmetric redundancies allows the separation of two BIRD functions: constraining SHORT-ROOT spread through nuclear retention and transcriptional regulation of key downstream SHORT-ROOT targets, including SCARECROW and CYCLIND6. Our data indicate that BIRD proteins promote formative divisions and tissue specification in the Arabidopsis thaliana root meristem ground tissue by tethering and regulating transcriptional competence of SHORT-ROOT complexes. As a result, a tissue boundary is not "locked in" after initial patterning like in many animal systems, but possesses considerable developmental plasticity due to continuous reliance on mobile transcription factors.
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Affiliation(s)
- Yuchen Long
- Plant Developmental Biology, Wageningen University, Wageningen 6708PB, The Netherlands Molecular Genetics, Department of Biology, Utrecht University, Utrecht 3581CH, The Netherlands
| | - Wouter Smet
- Plant Developmental Biology, Wageningen University, Wageningen 6708PB, The Netherlands Molecular Genetics, Department of Biology, Utrecht University, Utrecht 3581CH, The Netherlands
| | - Alfredo Cruz-Ramírez
- Molecular Genetics, Department of Biology, Utrecht University, Utrecht 3581CH, The Netherlands
| | - Bas Castelijns
- Molecular Genetics, Department of Biology, Utrecht University, Utrecht 3581CH, The Netherlands
| | - Wim de Jonge
- Molecular Genetics, Department of Biology, Utrecht University, Utrecht 3581CH, The Netherlands
| | - Ari Pekka Mähönen
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
| | - Benjamin P Bouchet
- Cell Biology, Faculty of Science, Utrecht University, Utrecht 3581CH, The Netherlands
| | - Gabino Sanchez Perez
- Bioinformatics, Plant Sciences, Wageningen University, Wageningen 6708PB, The Netherlands
| | - Anna Akhmanova
- Cell Biology, Faculty of Science, Utrecht University, Utrecht 3581CH, The Netherlands
| | - Ben Scheres
- Plant Developmental Biology, Wageningen University, Wageningen 6708PB, The Netherlands Molecular Genetics, Department of Biology, Utrecht University, Utrecht 3581CH, The Netherlands
| | - Ikram Blilou
- Plant Developmental Biology, Wageningen University, Wageningen 6708PB, The Netherlands Molecular Genetics, Department of Biology, Utrecht University, Utrecht 3581CH, The Netherlands
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22
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Rodriguez-Villalon A, Gujas B, van Wijk R, Munnik T, Hardtke CS. Primary root protophloem differentiation requires balanced phosphatidylinositol-4,5-biphosphate levels and systemically affects root branching. Development 2015; 142:1437-46. [PMID: 25813544 DOI: 10.1242/dev.118364] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 03/02/2015] [Indexed: 01/20/2023]
Abstract
Protophloem is a specialized vascular tissue in growing plant organs, such as root meristems. In Arabidopsis mutants with impaired primary root protophloem differentiation, brevis radix (brx) and octopus (ops), meristematic activity and consequently overall root growth are strongly reduced. Second site mutation in the protophloem-specific presumed phosphoinositide 5-phosphatase cotyledon vascular pattern 2 (CVP2), but not in its homolog CVP2-like 1 (CVL1), partially rescues brx defects. Consistent with this finding, CVP2 hyperactivity in a wild-type background recreates a brx phenotype. Paradoxically, however, while cvp2 or cvl1 single mutants display no apparent root defects, the root phenotype of cvp2 cvl1 double mutants is similar to brx or ops, although, as expected, cvp2 cvl1 seedlings contain more phosphatidylinositol-4,5-biphosphate. Thus, tightly balanced phosphatidylinositol-4,5-biphosphate levels appear essential for proper protophloem differentiation. Genetically, OPS acts downstream of phosphatidylinositol-4,5-biphosphate levels, as cvp2 mutation cannot rescue ops defects, whereas increased OPS dose rescues cvp2 cvl1 defects. Finally, all three mutants display higher density and accelerated emergence of lateral roots, which correlates with increased auxin response in the root differentiation zone. This phenotype is also created by application of peptides that suppress protophloem differentiation, clavata3/embryo surrounding region 26 (CLE26) and CLE45. Thus, local changes in the primary root protophloem systemically shape overall root system architecture.
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Affiliation(s)
- Antia Rodriguez-Villalon
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Bojan Gujas
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| | - Ringo van Wijk
- Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, Amsterdam 1098 XH, The Netherlands
| | - Teun Munnik
- Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, Amsterdam 1098 XH, The Netherlands
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
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23
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Cole RA, McInally SA, Fowler JE. Developmentally distinct activities of the exocyst enable rapid cell elongation and determine meristem size during primary root growth in Arabidopsis. BMC PLANT BIOLOGY 2014; 14:386. [PMID: 25551204 PMCID: PMC4302519 DOI: 10.1186/s12870-014-0386-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 12/15/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND Exocytosis is integral to root growth: trafficking components of systems that control growth (e.g., PIN auxin transport proteins) to the plasma membrane, and secreting materials that expand the cell wall to the apoplast. Spatiotemporal regulation of exocytosis in eukaryotes often involves the exocyst, an octameric complex that tethers selected secretory vesicles to specific sites on the plasma membrane and facilitates their exocytosis. We evaluated Arabidopsis lines with mutations in four exocyst components (SEC5, SEC8, EXO70A1 and EXO84B) to explore exocyst function in primary root growth. RESULTS The mutants have root growth rates that are 82% to 11% of wild-type. Even in lines with the most severe defects, the organization of the quiescent center and tissue layers at the root tips appears similar to wild-type, although meristematic, transition, and elongation zones are shorter. Reduced cell production rates in the mutants are due to the shorter meristems, but not to lengthened cell cycles. Additionally, mutants demonstrate reduced anisotropic cell expansion in the elongation zone, but not the meristematic zone, resulting in shorter mature cells that are similar in shape to wild-type. As expected, hypersensitivity to brefeldin A links the mutant root growth defect to altered vesicular trafficking. Several experimental approaches (e.g., dose-response measurements, localization of signaling components) failed to identify aberrant auxin or brassinosteroid signaling as a primary driver for reduced root growth in exocyst mutants. CONCLUSIONS The exocyst participates in two spatially distinct developmental processes, apparently by mechanisms not directly linked to auxin or brassinosteroid signaling pathways, to help establish root meristem size, and to facilitate rapid cell expansion in the elongation zone.
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Affiliation(s)
- Rex A Cole
- Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, 97331 OR USA
| | - Samantha A McInally
- Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, 97331 OR USA
| | - John E Fowler
- Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, 97331 OR USA
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De Vos D, Vissenberg K, Broeckhove J, Beemster GTS. Putting theory to the test: which regulatory mechanisms can drive realistic growth of a root? PLoS Comput Biol 2014; 10:e1003910. [PMID: 25358093 PMCID: PMC4214622 DOI: 10.1371/journal.pcbi.1003910] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 09/15/2014] [Indexed: 01/20/2023] Open
Abstract
In recent years there has been a strong development of computational approaches to mechanistically understand organ growth regulation in plants. In this study, simulation methods were used to explore which regulatory mechanisms can lead to realistic output at the cell and whole organ scale and which other possibilities must be discarded as they result in cellular patterns and kinematic characteristics that are not consistent with experimental observations for the Arabidopsis thaliana primary root. To aid in this analysis, a ‘Uniform Longitudinal Strain Rule’ (ULSR) was formulated as a necessary condition for stable, unidirectional, symplastic growth. Our simulations indicate that symplastic structures are robust to differences in longitudinal strain rates along the growth axis only if these differences are small and short-lived. Whereas simple cell-autonomous regulatory rules based on counters and timers can produce stable growth, it was found that steady developmental zones and smooth transitions in cell lengths are not feasible. By introducing spatial cues into growth regulation, those inadequacies could be avoided and experimental data could be faithfully reproduced. Nevertheless, a root growth model based on previous polar auxin-transport mechanisms violates the proposed ULSR due to the presence of lateral gradients. Models with layer-specific regulation or layer-driven growth offer potential solutions. Alternatively, a model representing the known cross-talk between auxin, as the cell proliferation promoting factor, and cytokinin, as the cell differentiation promoting factor, predicts the effect of hormone-perturbations on meristem size. By down-regulating PIN-mediated transport through the transcription factor SHY2, cytokinin effectively flattens the lateral auxin gradient, at the basal boundary of the division zone, (thereby imposing the ULSR) to signal the exit of proliferation and start of elongation. This model exploration underlines the value of generating virtual root growth kinematics to dissect and understand the mechanisms controlling this biological system. The growth of a plant root is driven by cell division and cell expansion occurring in spatially distinct developmental zones. Although these zones are in principle stable, depending on the conditions, their size and properties can be modulated. This has been meticulously described by kinematic studies, which have led to the proposal of mechanisms underpinning those observations. At the same time, much knowledge of the identities and interactions of molecules involved in these mechanisms has accumulated, in particular from the model species Arabidopsis thaliana. Here we attempt to resolve the longstanding question whether observed growth patterns can be explained by autonomous decision-making at the level of individual cells or if the aid of some external signal is required. We then ask, building on the accumulated molecular information, which minimal models can provide for stable growth while keeping sufficient flexibility to regulate growth. Therefore, we constructed computational models for different growth mechanisms operating in a virtual two-dimensional Arabidopsis root and compared their behaviour with biological experiments. The simulations provide strong indications that spatial signals are required for realistic and flexible root growth, likely orchestrated by the plant hormones auxin and cytokinin.
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Affiliation(s)
- Dirk De Vos
- Molecular Plant Physiology and Biotechnology, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Kris Vissenberg
- Plant Growth and Development, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Jan Broeckhove
- Computational Modelling and Programming, Department of Mathematics and Informatics, University of Antwerp, Antwerp, Belgium
| | - Gerrit T. S. Beemster
- Molecular Plant Physiology and Biotechnology, Department of Biology, University of Antwerp, Antwerp, Belgium
- * E-mail:
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25
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Sénéchal F, Wattier C, Rustérucci C, Pelloux J. Homogalacturonan-modifying enzymes: structure, expression, and roles in plants. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5125-60. [PMID: 25056773 PMCID: PMC4400535 DOI: 10.1093/jxb/eru272] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/20/2014] [Accepted: 05/22/2014] [Indexed: 05/18/2023]
Abstract
Understanding the changes affecting the plant cell wall is a key element in addressing its functional role in plant growth and in the response to stress. Pectins, which are the main constituents of the primary cell wall in dicot species, play a central role in the control of cellular adhesion and thereby of the rheological properties of the wall. This is likely to be a major determinant of plant growth. How the discrete changes in pectin structure are mediated is thus a key issue in our understanding of plant development and plant responses to changes in the environment. In particular, understanding the remodelling of homogalacturonan (HG), the most abundant pectic polymer, by specific enzymes is a current challenge in addressing its fundamental role. HG, a polymer that can be methylesterified or acetylated, can be modified by HGMEs (HG-modifying enzymes) which all belong to large multigenic families in all species sequenced to date. In particular, both the degrees of substitution (methylesterification and/or acetylation) and polymerization can be controlled by specific enzymes such as pectin methylesterases (PMEs), pectin acetylesterases (PAEs), polygalacturonases (PGs), or pectate lyases-like (PLLs). Major advances in the biochemical and functional characterization of these enzymes have been made over the last 10 years. This review aims to provide a comprehensive, up to date summary of the recent data concerning the structure, regulation, and function of these fascinating enzymes in plant development and in response to biotic stresses.
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Affiliation(s)
- Fabien Sénéchal
- EA3900 BIOPI Biologie des Plantes et Innovation, Université de Picardie Jules Verne, 33 Rue St Leu, F-80039 Amiens, France
| | - Christopher Wattier
- EA3900 BIOPI Biologie des Plantes et Innovation, Université de Picardie Jules Verne, 33 Rue St Leu, F-80039 Amiens, France
| | - Christine Rustérucci
- EA3900 BIOPI Biologie des Plantes et Innovation, Université de Picardie Jules Verne, 33 Rue St Leu, F-80039 Amiens, France
| | - Jérôme Pelloux
- EA3900 BIOPI Biologie des Plantes et Innovation, Université de Picardie Jules Verne, 33 Rue St Leu, F-80039 Amiens, France
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Hohm T, Demarsy E, Quan C, Allenbach Petrolati L, Preuten T, Vernoux T, Bergmann S, Fankhauser C. Plasma membrane H⁺ -ATPase regulation is required for auxin gradient formation preceding phototropic growth. Mol Syst Biol 2014; 10:751. [PMID: 25261457 PMCID: PMC4299663 DOI: 10.15252/msb.20145247] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Phototropism is a growth response allowing plants to align their photosynthetic organs toward
incoming light and thereby to optimize photosynthetic activity. Formation of a lateral gradient of
the phytohormone auxin is a key step to trigger asymmetric growth of the shoot leading to
phototropic reorientation. To identify important regulators of auxin gradient formation, we
developed an auxin flux model that enabled us to test in silico the impact of
different morphological and biophysical parameters on gradient formation, including the contribution
of the extracellular space (cell wall) or apoplast. Our model indicates that cell size, cell
distributions, and apoplast thickness are all important factors affecting gradient formation. Among
all tested variables, regulation of apoplastic pH was the most important to enable the formation of
a lateral auxin gradient. To test this prediction, we interfered with the activity of plasma
membrane H+-ATPases that are required to control apoplastic pH. Our results show
that H+-ATPases are indeed important for the establishment of a lateral auxin
gradient and phototropism. Moreover, we show that during phototropism, H+-ATPase
activity is regulated by the phototropin photoreceptors, providing a mechanism by which light
influences apoplastic pH.
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Affiliation(s)
- Tim Hohm
- Department of Medical Genetics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland Swiss Institute for Bioinformatics, Lausanne, Switzerland
| | - Emilie Demarsy
- Centre for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Clément Quan
- Centre for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Laure Allenbach Petrolati
- Centre for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Tobias Preuten
- Centre for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Teva Vernoux
- Laboratoire de Reproduction et Développement des Plantes, CNRS INRA ENS Lyon UCBL Université de Lyon, Lyon, France
| | - Sven Bergmann
- Department of Medical Genetics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland Swiss Institute for Bioinformatics, Lausanne, Switzerland
| | - Christian Fankhauser
- Centre for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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27
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Abstract
The phloem performs essential systemic functions in tracheophytes, yet little is known about its molecular genetic specification. Here we show that application of the peptide ligand CLAVATA3/embryo surrounding region 45 (CLE45) specifically inhibits specification of protophloem in Arabidopsis roots by locking the sieve element precursor cell in its preceding developmental state. CLE45 treatment, as well as viable transgenic expression of a weak CLE45(G6T) variant, interferes not only with commitment to sieve element fate but also with the formative sieve element precursor cell division that creates protophloem and metaphloem cell files. However, the absence of this division appears to be a secondary effect of discontinuous sieve element files and subsequent systemically reduced auxin signaling in the root meristem. In the absence of the formative sieve element precursor cell division, metaphloem identity is seemingly adopted by the normally procambial cell file instead, pointing to possibly independent positional cues for metaphloem formation. The protophloem formation and differentiation defects in brevis radix (brx) and octopus (ops) mutants are similar to those observed in transgenic seedlings with increased CLE45 activity and can be rescued by loss of function of a putative CLE45 receptor, barely any meristem 3 (BAM3). Conversely, a dominant gain-of-function ops allele or mild OPS dosage increase suppresses brx defects and confers CLE45 resistance. Thus, our data suggest that delicate quantitative interplay between the opposing activities of BAM3-mediated CLE45 signals and OPS-dependent signals determines cellular commitment to protophloem sieve element fate, with OPS acting as a positive, quantitative master regulator of phloem fate.
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28
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Ursache R, Miyashima S, Chen Q, Vatén A, Nakajima K, Carlsbecker A, Zhao Y, Helariutta Y, Dettmer J. Tryptophan-dependent auxin biosynthesis is required for HD-ZIP III-mediated xylem patterning. Development 2014; 141:1250-9. [PMID: 24595288 DOI: 10.1242/dev.103473] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The development and growth of higher plants is highly dependent on the conduction of water and minerals throughout the plant by xylem vessels. In Arabidopsis roots the xylem is organized as an axis of cell files with two distinct cell fates: the central metaxylem and the peripheral protoxylem. During vascular development, high and low expression levels of the class III HD-ZIP transcription factors promote metaxylem and protoxylem identities, respectively. Protoxylem specification is determined by both mobile, ground tissue-emanating miRNA165/6 species, which downregulate, and auxin concentrated by polar transport, which promotes HD-ZIP III expression. However, the factors promoting high HD-ZIP III expression for metaxylem identity have remained elusive. We show here that auxin biosynthesis promotes HD-ZIP III expression and metaxylem specification. Several auxin biosynthesis genes are expressed in the outer layers surrounding the vascular tissue in Arabidopsis root and downregulation of HD-ZIP III expression accompanied by specific defects in metaxylem development is seen in auxin biosynthesis mutants, such as trp2-12, wei8 tar2 or a quintuple yucca mutant, and in plants treated with L-kynurenine, a pharmacological inhibitor of auxin biosynthesis. Some of the patterning defects can be suppressed by synthetically elevated HD-ZIP III expression. Taken together, our results indicate that polar auxin transport, which was earlier shown to be required for protoxylem formation, is not sufficient to establish a proper xylem axis but that root-based auxin biosynthesis is additionally required.
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Affiliation(s)
- Robertas Ursache
- Institute of Biotechnology, Department of Bio and Environmental Sciences, University of Helsinki, FIN-00014, Finland
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29
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Schmidt T, Pasternak T, Liu K, Blein T, Aubry-Hivet D, Dovzhenko A, Duerr J, Teale W, Ditengou FA, Burkhardt H, Ronneberger O, Palme K. The iRoCS Toolbox--3D analysis of the plant root apical meristem at cellular resolution. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 77:806-14. [PMID: 24417645 DOI: 10.1111/tpj.12429] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 12/16/2013] [Accepted: 12/23/2013] [Indexed: 05/04/2023]
Abstract
To achieve a detailed understanding of processes in biological systems, cellular features must be quantified in the three-dimensional (3D) context of cells and organs. We described use of the intrinsic root coordinate system (iRoCS) as a reference model for the root apical meristem of plants. iRoCS enables direct and quantitative comparison between the root tips of plant populations at single-cell resolution. The iRoCS Toolbox automatically fits standardized coordinates to raw 3D image data. It detects nuclei or segments cells, automatically fits the coordinate system, and groups the nuclei/cells into the root's tissue layers. The division status of each nucleus may also be determined. The only manual step required is to mark the quiescent centre. All intermediate outputs may be refined if necessary. The ability to learn the visual appearance of nuclei by example allows the iRoCS Toolbox to be easily adapted to various phenotypes. The iRoCS Toolbox is provided as an open-source software package, licensed under the GNU General Public License, to make it accessible to a broad community. To demonstrate the power of the technique, we measured subtle changes in cell division patterns caused by modified auxin flux within the Arabidopsis thaliana root apical meristem.
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Affiliation(s)
- Thorsten Schmidt
- Institute for Computer Science, Albert Ludwigs University Freiburg, Georges Köhler Allee, Gebäude 52, D-79110, Freiburg, Germany
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30
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Band LR, Wells DM, Fozard JA, Ghetiu T, French AP, Pound MP, Wilson MH, Yu L, Li W, Hijazi HI, Oh J, Pearce SP, Perez-Amador MA, Yun J, Kramer E, Alonso JM, Godin C, Vernoux T, Hodgman TC, Pridmore TP, Swarup R, King JR, Bennett MJ. Systems analysis of auxin transport in the Arabidopsis root apex. THE PLANT CELL 2014; 26:862-75. [PMID: 24632533 PMCID: PMC4001398 DOI: 10.1105/tpc.113.119495] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/06/2014] [Accepted: 02/14/2014] [Indexed: 05/17/2023]
Abstract
Auxin is a key regulator of plant growth and development. Within the root tip, auxin distribution plays a crucial role specifying developmental zones and coordinating tropic responses. Determining how the organ-scale auxin pattern is regulated at the cellular scale is essential to understanding how these processes are controlled. In this study, we developed an auxin transport model based on actual root cell geometries and carrier subcellular localizations. We tested model predictions using the DII-VENUS auxin sensor in conjunction with state-of-the-art segmentation tools. Our study revealed that auxin efflux carriers alone cannot create the pattern of auxin distribution at the root tip and that AUX1/LAX influx carriers are also required. We observed that AUX1 in lateral root cap (LRC) and elongating epidermal cells greatly enhance auxin's shootward flux, with this flux being predominantly through the LRC, entering the epidermal cells only as they enter the elongation zone. We conclude that the nonpolar AUX1/LAX influx carriers control which tissues have high auxin levels, whereas the polar PIN carriers control the direction of auxin transport within these tissues.
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Affiliation(s)
- Leah R. Band
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Darren M. Wells
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - John A. Fozard
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Teodor Ghetiu
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Andrew P. French
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Michael P. Pound
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Michael H. Wilson
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Lei Yu
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Wenda Li
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Hussein I. Hijazi
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Jaesung Oh
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Simon P. Pearce
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Miguel A. Perez-Amador
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia–Consejo Superior de Investigaciones Científicas, Ciudad Politécnica de la Innovación, 46022 Valencia, Spain
| | - Jeonga Yun
- Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Eric Kramer
- Physics Department, Bard College at Simon’s Rock, Great Barrington, Massachusetts 01230
| | - Jose M. Alonso
- Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Christophe Godin
- Virtual Plants Project Team, Unité Mixte de Recherche, Amélioration Génétique des Plantes Méditerranéennes et Tropicales, Institut National de Recherche en Informatique et en Automatique/Centre de Coopération Internationale en Recherche Agronomique pour le Développement, 34095 Montpellier, France
| | - Teva Vernoux
- Laboratoire de Reproduction et Developpement des Plantes, CNRS, INRA, Ecole Normale Supérieure Lyon, Université Claude Bernard Lyon 1, Université de Lyon, 69364 Lyon, France
| | - T. Charlie Hodgman
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Tony P. Pridmore
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Ranjan Swarup
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - John R. King
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Malcolm J. Bennett
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
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31
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Kami C, Allenbach L, Zourelidou M, Ljung K, Schütz F, Isono E, Watahiki MK, Yamamoto KT, Schwechheimer C, Fankhauser C. Reduced phototropism in pks mutants may be due to altered auxin-regulated gene expression or reduced lateral auxin transport. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 77:393-403. [PMID: 24286493 DOI: 10.1111/tpj.12395] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 10/24/2013] [Accepted: 11/20/2013] [Indexed: 05/05/2023]
Abstract
Phototropism allows plants to orient their photosynthetic organs towards the light. In Arabidopsis, phototropins 1 and 2 sense directional blue light such that phot1 triggers phototropism in response to low fluence rates, while both phot1 and phot2 mediate this response under higher light conditions. Phototropism results from asymmetric growth in the hypocotyl elongation zone that depends on an auxin gradient across the embryonic stem. How phototropin activation leads to this growth response is still poorly understood. Members of the phytochrome kinase substrate (PKS) family may act early in this pathway, because PKS1, PKS2 and PKS4 are needed for a normal phototropic response and they associate with phot1 in vivo. Here we show that PKS proteins are needed both for phot1- and phot2-mediated phototropism. The phototropic response is conditioned by the developmental asymmetry of dicotyledonous seedlings, such that there is a faster growth reorientation when cotyledons face away from the light compared with seedlings whose cotyledons face the light. The molecular basis for this developmental effect on phototropism is unknown; here we show that PKS proteins play a role at the interface between development and phototropism. Moreover, we present evidence for a role of PKS genes in hypocotyl gravi-reorientation that is independent of photoreceptors. pks mutants have normal levels of auxin and normal polar auxin transport, however they show altered expression patterns of auxin marker genes. This situation suggests that PKS proteins are involved in auxin signaling and/or lateral auxin redistribution.
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Affiliation(s)
- Chitose Kami
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Genopode Building, 1015, Lausanne, Switzerland
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32
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Zhou J, Yu F, Wang X, Yang Y, Yu C, Liu H, Cheng Y, Yan C, Chen J. Specific expression of DR5 promoter in rice roots using a tCUP derived promoter-reporter system. PLoS One 2014; 9:e87008. [PMID: 24466314 PMCID: PMC3899362 DOI: 10.1371/journal.pone.0087008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 12/15/2013] [Indexed: 11/19/2022] Open
Abstract
Variation of transgene expression caused by either position effect at the insertion site or the promoter/enhancer elements employed for the expression of selectable marker genes has complicated phenotype characterization and caused misinterpretation. We have developed a reporter system in rice to analyze the influence of vector configuration, spacer and selectable marker gene promoter on the expression of the promoterless GUS reporter and DR5 promoter. Our results indicate that a spacer inserted between the reversed 35S promoter and the GUS reporter could reduce leaky expression of the reporter but was unable to block the nonspecific expression of DR5::GUS. Stacking the selectable marker unit in head to tail with the GUS reporter aided the gene specific expression of the GUS reporter under the DR5 promoter even when the 35S promoter is used for expression of the selectable marker. Compared to 35S under this configuration, a quick and distinctive expression of DR5::GUS was observed in the root cap, quiescent center and xylem cells in the root apical meristem by using the tCUP derived promoter (tCUP1) for selection, that is similar to the pattern obtained by a sensitive DR5 variant (DR5rev) in Arabidopsis. These data suggest a conserved property of the tCUP promoter in preventing enhancer-promoter interactions in rice as it does in Arabidopsis, and also demonstrate that an analogous distal auxin maximum exists in roots of rice. Therefore, the tCUP promoter based selection system provides a new strategy for specific expression of transgenes in rice.
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Affiliation(s)
- Jie Zhou
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA Key Laboratory for Plant Protection and Biotechnology, Zhejiang Provincial Key Laboratory of Plant Virology, Zhejiang Academy of Agricultural Sciences, Hangzhou, P. R. China
| | - Feibo Yu
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, P. R. China
| | - Xuming Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA Key Laboratory for Plant Protection and Biotechnology, Zhejiang Provincial Key Laboratory of Plant Virology, Zhejiang Academy of Agricultural Sciences, Hangzhou, P. R. China
| | - Yong Yang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA Key Laboratory for Plant Protection and Biotechnology, Zhejiang Provincial Key Laboratory of Plant Virology, Zhejiang Academy of Agricultural Sciences, Hangzhou, P. R. China
| | - Chulang Yu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA Key Laboratory for Plant Protection and Biotechnology, Zhejiang Provincial Key Laboratory of Plant Virology, Zhejiang Academy of Agricultural Sciences, Hangzhou, P. R. China
| | - Hongjia Liu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA Key Laboratory for Plant Protection and Biotechnology, Zhejiang Provincial Key Laboratory of Plant Virology, Zhejiang Academy of Agricultural Sciences, Hangzhou, P. R. China
| | - Ye Cheng
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA Key Laboratory for Plant Protection and Biotechnology, Zhejiang Provincial Key Laboratory of Plant Virology, Zhejiang Academy of Agricultural Sciences, Hangzhou, P. R. China
| | - Chengqi Yan
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA Key Laboratory for Plant Protection and Biotechnology, Zhejiang Provincial Key Laboratory of Plant Virology, Zhejiang Academy of Agricultural Sciences, Hangzhou, P. R. China
- * E-mail: (JC); (CY)
| | - Jianping Chen
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA Key Laboratory for Plant Protection and Biotechnology, Zhejiang Provincial Key Laboratory of Plant Virology, Zhejiang Academy of Agricultural Sciences, Hangzhou, P. R. China
- * E-mail: (JC); (CY)
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33
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de Reuille PB, Robinson S, Smith RS. Quantifying cell shape and gene expression in the shoot apical meristem using MorphoGraphX. Methods Mol Biol 2014; 1080:121-34. [PMID: 24132424 DOI: 10.1007/978-1-62703-643-6_10] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Confocal microscopy is a technique widely used to live-image plant tissue. Cells can be visualized by using fluorescent probes that mark the cell wall or plasma membrane. This enables the confocal microscope to be used as a 3D scanner with submicron precision. Here we present a protocol using the 3D image processing software MorphoGraphX (http://www.MorphoGraphX.org) to extract the surface geometry and cell shapes in the shoot apex. By segmenting cells over consecutive time points, precise growth maps of the shoot apex can be produced. It is also possible to tag a protein of interest with a fluorescent marker and quantify protein expression at the cellular level.
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Affiliation(s)
- Pierre Barbier de Reuille
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Köln, Germany
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34
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Korbei B, Luschnig C. Plasma membrane protein ubiquitylation and degradation as determinants of positional growth in plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:809-23. [PMID: 23981390 DOI: 10.1111/jipb.12059] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/16/2013] [Indexed: 05/08/2023]
Abstract
Being sessile organisms, plants evolved an unparalleled plasticity in their post-embryonic development, allowing them to adapt and fine-tune their vital parameters to an ever-changing environment. Crosstalk between plants and their environment requires tight regulation of information exchange at the plasma membrane (PM). Plasma membrane proteins mediate such communication, by sensing variations in nutrient availability, external cues as well as by controlled solute transport across the membrane border. Localization and steady-state levels are essential for PM protein function and ongoing research identified cis- and trans-acting determinants, involved in control of plant PM protein localization and turnover. In this overview, we summarize recent progress in our understanding of plant PM protein sorting and degradation via ubiquitylation, a post-translational and reversible modification of proteins. We highlight characterized components of the machinery involved in sorting of ubiquitylated PM proteins and discuss consequences of protein ubiquitylation on fate of selected PM proteins. Specifically, we focus on the role of ubiquitylation and PM protein degradation in the regulation of polar auxin transport (PAT). We combine this regulatory circuit with further aspects of PM protein sorting control, to address the interplay of events that might control PAT and polarized growth in higher plants.
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Affiliation(s)
- Barbara Korbei
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria
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35
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Suppression of Arabidopsis protophloem differentiation and root meristem growth by CLE45 requires the receptor-like kinase BAM3. Proc Natl Acad Sci U S A 2013; 110:7074-9. [PMID: 23569225 DOI: 10.1073/pnas.1222314110] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Peptide signaling presumably occupies a central role in plant development, yet only few concrete examples of receptor-ligand pairs that act in the context of specific differentiation processes have been described. Here we report that second-site null mutations in the Arabidopsis leucine-rich repeat receptor-like kinase gene barely any meristem 3 (BAM3) perfectly suppress the postembryonic root meristem growth defect and the associated perturbed protophloem development of the brevis radix (brx) mutant. The roots of bam3 mutants specifically resist growth inhibition by the CLAVATA3/ENDOSPERM SURROUNDING REGION 45 (CLE45) peptide ligand. WT plants transformed with a construct for ectopic overexpression of CLE45 could not be recovered, with the exception of a single severely dwarfed and sterile plant that eventually died. By contrast, we obtained numerous transgenic bam3 mutants transformed with the same construct. These transgenic plants displayed a WT phenotype, however, supporting the notion that CLE45 is the likely BAM3 ligand. The results correlate with the observation that external CLE45 application represses protophloem differentiation in WT, but not in bam3 mutants. BAM3, BRX, and CLE45 are expressed in a similar spatiotemporal trend along the developing protophloem, up to the end of the transition zone. Induction of BAM3 expression upon CLE45 application, ectopic overexpression of BAM3 in brx root meristems, and laser ablation experiments suggest that intertwined regulatory activity of BRX, BAM3, and CLE45 could be involved in the proper transition of protophloem cells from proliferation to differentiation, thereby impinging on postembryonic growth capacity of the root meristem.
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Lee Y, Lee WS, Kim SH. Hormonal regulation of stem cell maintenance in roots. JOURNAL OF EXPERIMENTAL BOTANY 2013. [PMID: 23183258 DOI: 10.1093/jxb/ers331] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
During plant embryogenesis, the apical-basal axis is established and both the shoot apical meristem (SAM) and the root apical meristem (RAM) are formed. In both meristems, there are slowly dividing cells which control the differentiation of their surrounding cells called the organizing centre (OC) and the quiescent centre (QC) in the shoot and root, respectively. These centres with their surrounding initial cells form a 'stem cell niche'. The initial cells eventually differentiate into various plant tissues, giving rise to plant organs such as lateral shoots, flowers, leaves, and lateral roots. Plant hormones are important factors involved in the balance between cell division and differentiation such that plant growth and development are tightly controlled in space and time. No single hormone acts by itself in regulating the meristematic activity in the root meristem. Division and differentiation are controlled by interactions between several hormones. Intensive research on plant stem cells has focused on how cell division is regulated to form specific plant organs and tissues, how differentiation is controlled, and how stem cell fate is coordinated. In this review, recent knowledge pertaining to the role of plant hormones in maintaining root stem cells including the QC is summarized and discussed. Furthermore, we suggest diverse approaches to answering the main question of how root stem cells are regulated and maintained by plant hormones.
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Affiliation(s)
- Yew Lee
- Division of Biological Science and Technology, Yonsei University, Wonju 220-710, Republic of Korea
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Bargmann BOR, Vanneste S, Krouk G, Nawy T, Efroni I, Shani E, Choe G, Friml J, Bergmann DC, Estelle M, Birnbaum KD. A map of cell type-specific auxin responses. Mol Syst Biol 2013; 9:688. [PMID: 24022006 PMCID: PMC3792342 DOI: 10.1038/msb.2013.40] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 07/23/2013] [Indexed: 12/31/2022] Open
Abstract
In plants, changes in local auxin concentrations can trigger a range of developmental processes as distinct tissues respond differently to the same auxin stimulus. However, little is known about how auxin is interpreted by individual cell types. We performed a transcriptomic analysis of responses to auxin within four distinct tissues of the Arabidopsis thaliana root and demonstrate that different cell types show competence for discrete responses. The majority of auxin-responsive genes displayed a spatial bias in their induction or repression. The novel data set was used to examine how auxin influences tissue-specific transcriptional regulation of cell-identity markers. Additionally, the data were used in combination with spatial expression maps of the root to plot a transcriptomic auxin-response gradient across the apical and basal meristem. The readout revealed a strong correlation for thousands of genes between the relative response to auxin and expression along the longitudinal axis of the root. This data set and comparative analysis provide a transcriptome-level spatial breakdown of the response to auxin within an organ where this hormone mediates many aspects of development.
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Affiliation(s)
- Bastiaan O R Bargmann
- Biology Department, Center for Genomics and Systems Biology, New York University, New York, NY, USA
- Department of Cell and Developmental Biology, UCSD, La Jolla, CA, USA
| | - Steffen Vanneste
- Department of Plant Systems Biology, VIB, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Gabriel Krouk
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes—Claude Grignon, Montpellier, France
| | - Tal Nawy
- Biology Department, Center for Genomics and Systems Biology, New York University, New York, NY, USA
| | - Idan Efroni
- Biology Department, Center for Genomics and Systems Biology, New York University, New York, NY, USA
| | - Eilon Shani
- Department of Cell and Developmental Biology, UCSD, La Jolla, CA, USA
| | - Goh Choe
- Department of Cell and Developmental Biology, UCSD, La Jolla, CA, USA
| | - Jiří Friml
- Department of Plant Systems Biology, VIB, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | | | - Mark Estelle
- Department of Cell and Developmental Biology, UCSD, La Jolla, CA, USA
| | - Kenneth D Birnbaum
- Biology Department, Center for Genomics and Systems Biology, New York University, New York, NY, USA
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Natural Arabidopsis brx Loss-of-Function Alleles Confer Root Adaptation to Acidic Soil. Curr Biol 2012; 22:1962-8. [DOI: 10.1016/j.cub.2012.08.026] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 07/19/2012] [Accepted: 08/14/2012] [Indexed: 01/06/2023]
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Niklas KJ, Kutschera U. Plant development, auxin, and the subsystem incompleteness theorem. FRONTIERS IN PLANT SCIENCE 2012; 3:37. [PMID: 22645582 PMCID: PMC3355799 DOI: 10.3389/fpls.2012.00037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 02/13/2012] [Indexed: 05/08/2023]
Abstract
Plant morphogenesis (the process whereby form develops) requires signal cross-talking among all levels of organization to coordinate the operation of metabolic and genomic subsystems operating in a larger network of subsystems. Each subsystem can be rendered as a logic circuit supervising the operation of one or more signal-activated system. This approach simplifies complex morphogenetic phenomena and allows for their aggregation into diagrams of progressively larger networks. This technique is illustrated here by rendering two logic circuits and signal-activated subsystems, one for auxin (IAA) polar/lateral intercellular transport and another for IAA-mediated cell wall loosening. For each of these phenomena, a circuit/subsystem diagram highlights missing components (either in the logic circuit or in the subsystem it supervises) that must be identified experimentally if each of these basic plant phenomena is to be fully understood. We also illustrate the "subsystem incompleteness theorem," which states that no subsystem is operationally self-sufficient. Indeed, a whole-organism perspective is required to understand even the most simple morphogenetic process, because, when isolated, every biological signal-activated subsystem is morphogenetically ineffective.
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Affiliation(s)
- Karl J. Niklas
- Department of Plant Biology, Cornell UniversityIthaca, NY, USA
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Brunoud G, Wells DM, Oliva M, Larrieu A, Mirabet V, Burrow AH, Beeckman T, Kepinski S, Traas J, Bennett MJ, Vernoux T. A novel sensor to map auxin response and distribution at high spatio-temporal resolution. Nature 2012; 482:103-6. [PMID: 22246322 DOI: 10.1038/nature10791] [Citation(s) in RCA: 492] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 12/19/2011] [Indexed: 02/07/2023]
Abstract
Auxin is a key plant morphogenetic signal but tools to analyse dynamically its distribution and signalling during development are still limited. Auxin perception directly triggers the degradation of Aux/IAA repressor proteins. Here we describe a novel Aux/IAA-based auxin signalling sensor termed DII-VENUS that was engineered in the model plant Arabidopsis thaliana. The VENUS fast maturing form of yellow fluorescent protein was fused in-frame to the Aux/IAA auxin-interaction domain (termed domain II; DII) and expressed under a constitutive promoter. We initially show that DII-VENUS abundance is dependent on auxin, its TIR1/AFBs co-receptors and proteasome activities. Next, we demonstrate that DII-VENUS provides a map of relative auxin distribution at cellular resolution in different tissues. DII-VENUS is also rapidly degraded in response to auxin and we used it to visualize dynamic changes in cellular auxin distribution successfully during two developmental responses, the root gravitropic response and lateral organ production at the shoot apex. Our results illustrate the value of developing response input sensors such as DII-VENUS to provide high-resolution spatio-temporal information about hormone distribution and response during plant growth and development.
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Affiliation(s)
- Géraldine Brunoud
- Laboratoire de Reproduction et Développement des Plantes, CNRS, INRA, ENS Lyon, UCBL, Université de Lyon, 69364 Lyon, France
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